The Collaborative International Dictionary of English v.0.48:

Inventive \In*vent"ive\, a. [Cf. F. inventif.]
   Able and apt to invent; quick at contrivance; ready at
   expedients; as, an inventive head or genius. --Dryden. --
   In*vent"ive*ly, adv. -- In*vent"ive*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inventive
    adj 1: (used of persons or artifacts) marked by independence and
           creativity in thought or action; "an imaginative use of
           material"; "the invention of the knitting frame by
           another ingenious English clergyman"- Lewis Mumford; "an
           ingenious device"; "had an inventive turn of mind";
           "inventive ceramics" [syn: imaginative, inventive]

Moby Thesaurus II by Grady Ward, 1.0:

123 Moby Thesaurus words for "inventive":
   Machiavellian, Machiavellic, abecedarian, aboriginal, acute,
   antenatal, arch, artful, astute, autochthonous, beginning, budding,
   cagey, canny, causative, clever, conceptive, conceptual,
   constructive, crafty, creative, cunning, cute, deceitful, deep,
   deep-laid, demiurgic, designing, diplomatic, elemental, elementary,
   embryonic, esemplastic, fecund, feline, fertile, fetal, formative,
   foundational, foxy, fruitful, fundamental, generative, germinal,
   gestatory, guileful, ideational, ideative, imaginative, in embryo,
   in its infancy, in the bud, inaugural, inceptive, inchoate,
   inchoative, incipient, incunabular, infant, infantile, ingenious,
   initial, initiative, initiatory, innovational, innovative,
   insidious, inspired, introductory, knowing, nascent, natal,
   notional, original, originative, parturient, pawky, politic,
   postnatal, pregnant, prenatal, primal, primary, prime, primeval,
   primitive, primogenial, procreative, productive, prolific, ready,
   resourceful, rudimental, rudimentary, scheming, seminal,
   serpentine, shaping, sharp, shifty, shrewd, slick, slippery, sly,
   smooth, snaky, sneaky, sophistical, stealthy, strategic, subtile,
   subtle, supple, tactical, teeming, trickish, tricksy, tricky, ur,
   visioned, vulpine, wary, wily